Many people have pointed out that this probably relates to the end of the Hasbro fiscal year and the need to please shareholders.
And they would be wrong.
WotC is a division of Hasbro. There are no publicly-traded shares of WotC stock. Layoffs at WotC might be a short-term fix/attempt to drawing WotC expenses in line, but the fact that this happens almost every year would point to a poorly run division, one that is not as profitable as it should be in the eyes of WotC execs or Hasbro execs, or both. D&D is a small slice of a division, which is a small slice of the parent company. WotC layoffs likely equate to a rounding a decimal from a Hasbro point of view.
In the limited ability for an outsider to perform an analysis of what's going on & why, it would be relevant to know the following:
1. Do the (mostly) annual WotC layoffs extend to other product lines or just D&D? If it's across the board, then it's a managerial practice. If it's just specific product lines, then someone's turning a critical eye towards that line.
2. Does Hasbro have similiar annual layoffs across other divisions & product lines? If so, then this is likely a practice that originated with Hasbro. While reducing expenses may result in greater profits (sales have to stay consistent or increase, however), they'd have to be sizeable cuts to increase profitablility and result in a better stock price and return to shareholders.
This far into the cycle, however, the fantasy of the evil overlord of Hasbro forcing WotC to do things rings false. If Hasbro was this heavy-handed and was doing this solely to reduce expenses, then they should wipe out the WotC execs as the execs presumably make more than designers, etc. Since this hasn't happened, and since WotC continues to have its own executive & managerial staff, I contend that these are WotC decisions.
If the theory cited in #2 above turns out to be true, then the WotC execs are toeing the company line. But they're still picking who's getting the axe.
I know many gamers like to think of Hasbro as the corporate suits & WotC as "gamers like us", but it's a business first folks. Fantasies you tell yourself so you can feel better about supporting the brand doesn't change that.